Method for fabricating semiconductor components

ABSTRACT

A method for fabricating semiconductor components is performed using a laser scanner and a laser imaging process. A substrate, such as a semiconductor wafer, containing multiple semiconductor components, such as dice or packages, is provided. The components include integrated circuits, and component contacts in electrical communication with the integrated circuits. Initially, the components are tested to identify and locate good components and defective components on the substrate. Using data from the testing step and the laser scanner, patterns of conductors are then formed to either repair the defective components, to electrically isolate the defective components for burn-in, or to form component clusters containing only the good components. Alternately, using data from the testing step and the laser scanner, a matching test board can be fabricated, and used to electrically engage the good components, while the defective components remain isolated.

FIELD OF THE INVENTION

This invention relates generally to semiconductor manufacture andtesting, and more particularly to a method for fabricating and testingsemiconductor components.

BACKGROUND OF THE INVENTION

Photolithography is widely used in semiconductor manufacture and otherapplications. During photolithography, an exposure energy, such asultraviolet light, is passed through a mask and onto a target such as asemiconductor wafer. The mask contains opaque and transparent regionswhich form a primary mask pattern. The exposure energy exposes the maskpattern on a layer of resist deposited on the target. Followingexposure, the layer of resist can be developed to form a resist mask. Insemiconductor manufacture, such a resist mask can be used for etching,ion implantation, screen printing, CVD and other processes.

One recently developed form of lithography uses a laser scanner to focusmodulated laser beams in a series of scan lines onto a radiant sensitivefilm of resist. This technique eliminates the mask, as the pattern iswritten directly onto the resist. A conventional laser scanner includesa laser adapted to generate a collimated light beam, that can be splitinto an array of collimated sub beams. Typically, the laser beamcomprises ultraviolet light having a wavelength of 325 nm or 363.8 nm.The laser scanner also includes a modulator, such as an acousto-opticmodulator, adapted to receive a data signal in digital form, and tomodulate the laser beam responsive to the data signal. In addition, thelaser scanner includes scan optics, such as a rotating reflectivepolygon, adapted to form an image of the beam and to sweep the imageacross a scan line. The laser scanner also includes a precision stageadapted to move the target in X and Y directions approximatelyperpendicular to the scan line direction.

The present invention employs a laser scanner and direct laser imagingto improve various wafer level fabrication and test processes forsemiconductor components. For example, semiconductor dice, semiconductorpackages, and semiconductor interconnects are typically fabricated on asingle substrate (e.g., wafer or panel) that is subsequently singulatedinto individual components. These processes are sometimes referred to asbeing “wafer level” processes.

One shortcoming of wafer level fabrication processes is that some of thecomponents on the substrate can be defective. For example, defects canoccur in the integrated circuits contained on the components, in theaddress circuitry for the components, or in the configuration of thearrays of semiconductor devices on the components. Some defects can makea component non-functional, while other defects merely affect theelectrical characteristics of the component.

The defective components can decrease the yield of the substrate andaffect the quality of the singulated components. In addition, thedefective components can compromise subsequent test procedures,particularly wafer level burn-in tests. For example, conventionalburn-in boards utilize “shared resources” wherein multiple componentsare electrically connected in series, and the same test signals areapplied to multiple components. Defective components can short the testsignals, and adversely affect the test process.

Rather than having specific defects, other semiconductor components canhave electrical characteristics that do not meet certain standards. Forexample, one important electrical characteristic is the speed with whichthe components process signals. Some functional components can havespeed characteristics that make the components unsuitable for aparticular application. Again the substandard components can decreasethe yield of the substrate.

The present invention utilizes a laser scanner and direct laser imagingto improve wafer level fabrication and test processes for semiconductorcomponents.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method for fabricating andtesting semiconductor components is provided. Also provided are improvedsemiconductor components fabricated using the method, and a systemconfigured to perform the method.

Initially, a substrate having a plurality of semiconductor components isprovided. For example, the substrate can comprises a semiconductorwafer, or a portion thereof, containing multiple semiconductor dice orsemiconductor packages. In addition, the components on the substrate caninclude component contacts, such as bond pads, in electricalcommunication with integrated circuits contained on the components.

As a first step, the components on the substrate are tested to“evaluate” and “map” the components. The testing step can include“functional” tests for evaluating a gross functionality of thecomponents, as well as “parametric” tests for evaluating variouselectrical characteristics of the components (e.g., speed). The testingstep identifies and locates both “defective” components and “good”components on the substrate.

A metal redistribution layer is then blanket deposited on the substrate,and on the component contacts. Next, a radiant sensitive film, such as awet film resist, or a dry film resist, is blanket deposited on theredistribution layer. The radiant sensitive film is then exposed using alaser scanner programmed with digital data representative of a desiredpattern of conductors. In addition, the digital data includes test datafrom the initial testing step. Development of the exposed radiantsensitive film forms a mask that can be used to etch the pattern ofconductors on each component. Such an etching process is known in theart as a “subtractive” process. However, a laser imaged mask can also beused to form the conductors using an additive process (i.e., depositionof a metal through the mask).

The conductors are-configured to “fan out”, or other wise locate,terminal contacts for the components in a required pattern, such as agrid array. In addition, using the test data, the conductors can beconfigured to repair or re-configure selected components, such asdefective or substandard components. Alternately, the conductors can beconfigured to isolate defective components for wafer level burn-in, orto form component clusters configured to improve “wafer yield” byexcluding selected components.

As another alternative, using the test data, a matching test board canbe fabricated that is configured to electrically engage the goodcomponents on the wafer, while the defective components are electricallyisolated. The test board can also be fabricated using a laser scannerand a laser imaging process employing essentially the same data used topattern the redistribution layer.

In an alternate embodiment of the method, a semiconductor package isfabricated with a solder mask, or a rigidifying mask, patterned using alaser scanner and a laser imaging process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating steps in the method of theinvention for fabricating semiconductor components;

FIGS. 2A-2F are schematic cross sectional views illustrating broad stepsin a “subtractive” embodiment of the method;

FIGS. 2G-2J are schematic cross sectional views illustrating broad stepsin an “additive” embodiment of the method;

FIG. 3 is a schematic diagram of a laser scanner suitable for performinga laser imaging step of the method;

FIG. 3A is a partially cut away plan view taken along line 3A—3A ofFigure.3 illustrating a semiconductor substrate during laser imaging;

FIG. 4 is a plan view of the semiconductor substrate during a testingstep of the method;

FIG. 5 is a plan view of the semiconductor substrate during a clusteringstep of the method;

FIG. 6 is a plan view of the semiconductor substrate and a test boardconstructed in accordance with the invention;

FIG. 7 is a side elevation view of a semiconductor package constructedin accordance with the invention;

FIG. 7A is a bottom view of the package taken along line 7A—7A of FIG.7;

FIG. 7B is an enlarged cross sectional view of the package taken alongsection line 7B—7B of FIG. 7A; and

FIGS. 8A-8D are schematic cross sectional views illustrating steps in analternate embodiment of the invention for constructing a semiconductorcomponent with a solder mask or a rigidifying mask.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, and to FIGS. 2A-2F, broad steps in a method forfabricating semiconductor components in accordance with the inventionare illustrated. In the illustrative embodiment the components comprisesemiconductor dice, or semiconductor packages (e.g., chip scale packagesor minimally packaged dice).

Initially, as shown in FIG. 2A, a semiconductor substrate 10 containinga plurality of semiconductor components 12 is provided. For example, thesubstrate 10 can comprise a wafer, or a portion thereof, made of aconventional semiconductor material, such as silicon or galliumarsenide, on which semiconductor dice have been formed using well knownprocesses, such as doping, CVD and etching. As another example, thesubstrate 10 can comprise a panel containing a plurality ofsemiconductor packages. In this case the substrate 10 can be made of anorganic material, such as a glass filled resin, such as epoxy glass(FR-4), polyimide glass, or a cyanate-glass material. In either case,the components 12 include integrated circuits and component contacts 28(FIG. 3A), such as bond pads, in electrical communication with theintegrated circuits contained on the components 12.

Next, as shown in FIG. 2B, the components 12 are tested on the substrate10 to “evaluate” and “map” the components 12. For example, the testingstep can be used to “identify” defective components 12D (FIG. 4) and to“locate” the defective components 12D, as well as the “good” components12. The testing step can be performed using techniques and equipmentthat are known in the art.

As used herein the term “evaluate” means to measure or assess variousphysical or electrical characteristics of the components 12.

The term “map” means to determine a location of “defective” and “good”components on the substrate.

The term “defective component” means a component having electricalcharacteristics that do not meet required standards for a particularapplication. For example, physical and electrical defects, such as shortcircuits, open circuits, leaking contacts, and cracked insulatinglayers, can make a component non-functional and thus defective.Alternately, a functional component may not have an identifiablephysical or electrical defect, yet can still be considered defective fora particular application. For example, a component that does not meet arequired standard for speed may be considered “functional” yet“defective” for making chip scale packages. However, the component maynot be defective for other applications, such as making conventionalplastic semiconductor packages.

The term “good component” means a component having electricalcharacteristics that meet required standards for a particularapplication.

One well known wafer level test is referred to as wafer probe. Forperforming a wafer probe, a tester containing test circuitry 14 (FIG.2B) is provided. The test circuitry 14 is configured to generate andapply test signals to the integrated circuits and electrical devicescontained on the components 12. Also provided is a probe card 16 inelectrical communication with the test circuitry 14. The probe card 16includes probe contacts 18 configured to electrically engage thecomponent contacts 28 (FIG. 3A), and to provide separate electricalpaths for applying the test signals to the components 12.

In general, the test circuitry 14 can be configured to test variouselectrical characteristics of the components 12. One electricalcharacteristic that can be evaluated is the “gross functionality” ofeach component 12. Such a test can include powering up an individualcomponent 12, and then performing write, modify, or read operations oneach of the data paths (i.e., DQs) into and out of the component 12. Forexample, in the case of a 4× die, zeros can be written to each of thefour DQ's (four memory. cells) and read. Next, the zeros can be changedto “is” and checked to confirm the change has occurred. If the changeoccurs, the die is referred to as being “grossly” functional.

As another example, the test circuitry 14 can be configured to detectcell to cell defects in components 12 that contain memory cells. Todetect cell to cell defects, high voltage values (logical “1”) can bewritten to selected memory cells of an individual component 12. At thesame time low voltage values (logical “0”) can be written to adjacentmemory cells. The test circuitry 14 then determines whether the adjacentmemory cells maintain a logical “0” value. If not, then the logical “1”value written to the selected memory cells has shorted, indicating acell defect.

Another test that can be performed using the test circuitry 14 (FIG. 2B)is known as a “Walking 1” test. With a “Walking 1” test, an entire arrayon a component 12 is set to zeros and a “1” is written to the firstaddress. The “1” is then read. As a next step, the entire array is setto zeros, a “1” is written to the second address, and then read. Thisprocedure is repeated through all of the addresses of the array.

The test circuitry 14 can also be configured to test for opens, shorts,and current leakage between the component contacts 28 (FIG. 3A) on eachcomponent 12. Opens and shorts can be detected using a continuitycircuit configured to test for opens and shorts between selectedcomponent contacts 28.

In general each of the above test procedures is referred to as“functional testing”. However, the testing step can also include“parametric testing” such as speed grading or bin sorting. In this casethe electrical characteristics relative to the “performance” of thecomponents are evaluated. The parametric testing can be used to identifycomponents on the substrate 10 that are functional, but which may notpossess certain characteristics. For example, some of the components 12may be faster than other of the components 12 and more suitable forparticular applications.

In general the faster components are termed as “premium” components, andcommand a higher price. Other of the components 12 may be completelyfunctional, yet not able to meet premium standards.

Following the initial wafer level test to evaluate the components 12,and as shown in FIG. 2C, a metal redistribution layer 20 is blanketdeposited on the surface of the substrate 10 and on the componentcontacts 28 (FIG. 3A). The redistribution layer 20 can be deposited to adesired thickness using a suitable deposition process such as CVD,PECVD, LPCVD or sputtering. The redistribution layer 20 will besubsequently patterned to form patterns of conductors 22 (FIG. 2F) onthe components 12. In addition, the conductors 22 can be configured tolocate or “fan out” terminal contacts (e.g., solder balls) for thecomponents 12 in a desired pattern, such as a dense grid array.Redistribution layers are well known in the art of semiconductormanufacture for configuring different types of components. For example,semiconductor dice can be fabricated with bond pads in standardconfigurations. U.S. Pat. No. 6,048,753 to Farnworth et al. discloses astandardized bonding location process and apparatus.

Next, as shown in FIG. 2D, a radiant sensitive film 24 is formed on theredistribution layer 20. The radiant sensitive film 24 will besubsequently exposed and developed to form a mask 25 (FIG. 2F) foretching the redistribution layer 20 to form the patterns of conductors22 (FIG. 2F). The radiant sensitive film 24 can comprise a conventional“wet film” photo resist configured for exposure by UV radiation.Exemplary photo resists are manufactured by Shipley under the trademarks“APEX-E” and “UV-III”. The wet film photo resist can be formed as alayer with a desired thickness (e.g., 10,000 Å to 15,000 Å) using aconventional deposition process, such as a “spin on” process, followedby “soft bake” if required.

As another alternative, the radiant sensitive film 24 can comprise a“dry film” photopolymer resist manufactured by E.I. duPont de Nemoursand Company under the trademark “RISTON”. One suitable resist isdesignated “RISTON” LaserSeries LDI 300 hi-speed direct imaging resist.These dry film resists can be applied to the redistribution layer usinga laminator apparatus and a lamination process.

Next, as shown in FIG. 2E, the radiant sensitive film 24 is exposedusing a laser imaging process. For laser imaging the radiant sensitivefilm 24, a laser scanner 26 (FIG. 3) is provided. The laser scanner 26can be a commercially available unit available from a manufacturer suchas Etec Systems, Inc., of Hayward, Calif. and Tucson, Ariz. One suitablelaser scanner manufactured by Etec Systems, Inc. is the “DIGIRITE 2000”UV Laser Direct Imaging System. Other laser scanners are described inU.S. Pat. Nos. 5,255,051; 5,327,338; 5,386,221; and 6,037,967.

A conventional laser scanner 26 is illustrated schematically in FIG. 3.The laser scanner 26 includes a laser 30 configured to generate a laserbeam 32. For example, the laser beam 32 can comprise ultraviolet lightat a selected wavelength (e.g., 325 nm (nanometers) or 363.8 nm), pulsedat a frequency of from 1 to 300 MHz.

The laser scanner 26 also includes a modulator 34 having an opticalinput port configured to receive the laser beam 32. In addition, themodulator 34 includes an electrical input port configured to receivedigital data 36 (i.e., software). The digital data 36 represents aselected pattern that will be “written” or “laser imaged” on the radiantsensitive film 24. In addition, the laser beam 32 is typically splitinto a plurality of separate beams such that the modulator 34individually modulates each separate beam. As will be further explained,the digital data 36 also includes test data obtained during the initialtesting step, as previously outlined, and shown in FIG. 2B. For example,the test data 36 can indicate the location of the defective components12D (FIG. 4), and the location of defective component contacts 28 (FIG.3A). Similarly, the digital data 36 can indicate the locations of the“good” components 12 on the substrate 10.

Still referring to FIG. 3, the laser scanner 26 also includes a rotatingpolygon 38 configured to receive a modulated laser beam 40 from themodulator 34. The rotating polygon 38 includes reflective facets whichtransmit a modulated and reflected laser beam 42 onto a scan lens 44.The scan lens 44 focuses modulated, reflected and focused laser beams 46onto the radiant sensitive film 24. The modulated, reflected and focusedlaser beam 46 exposes the radiant sensitive film 24 such that followinga subsequent development step, the desired pattern is contained on theradiant sensitive film 24.

As shown in FIG. 2F, following exposure and development, the radiantsensitive film 24 forms a mask 25 that can be used to etch theredistribution layer 20 with the pattern of conductors 22. Either a wetor a dry etch process can be used to etch the redistribution layer 20 toform the conductors 22. Following this etch step, the mask 25 can be“stripped” or “lifted off” using a suitable process.

Although the method of the invention has been illustrated using asubtractive process (i.e., etching through the mask 25 to form theconductors 22), it is to be understood that the method of the inventioncan also be practiced using an additive process (i.e., depositionthrough a mask to form the conductors 22). Such an additive process isillustrated in FIGS. 2G-2J.

Initially, as shown in FIG. 2G, a radiant sensitive film 24AD is formedon the components 12, and on the substrate 10, substantially aspreviously described. Next, as shown in FIG. 2H, the radiant sensitivefilm 24AD is exposed using the laser scanner 26 and a laser imagingprocess substantially as previously described. As shown in FIG. 2I,development of the exposed radiant sensitive film 24AD forms a mask25AD. The mask 25AD includes mask openings in a required pattern forforming the conductors 22. The conductors 22 can be deposited into themask openings using a suitable process such as screen printing,squeegeeing or evaporating a conductive film. Next, as shown in FIG. 2Jthe mask 25AD is stripped or “lifted off” leaving the pattern ofconductors 22.

Referring again to FIG. 1, the redistribution layer 20 can be etchedwith the conductors 22 in patterns selected to achieve differentobjectives. As a first example, the redistribution layer 20 can beetched to repair or re-configure defective components 12D (FIGS. 4 and5). Specifically, the initial testing step identifies the defectivecomponents 12D and this information is contained in the digital data 36(FIG. 3) supplied to the modulator 34. Some defects can be corrected byproviding conductors 22 that substitute redundant circuitry contained onthe defective components 12D for defective circuitry.

Other defects can be corrected by configuring or re configuring thecomponent 12D in a particular electrical format. For example, a memorycomponent (e.g., DRAM) may be defective when configured as a 1 Meg×16device (i.e., 1 megabit deep by 16 bits wide=16 megabits of totalmemory). However, the memory component may not be defective whenconfigured as a 4 Meg×4 device (i.e., 4 megabits deep by 4 bits wide=16megabits of total memory). By electrically connecting, or alternatelyelectrically isolating, selected component contacts 28 using theconductors 22 different configurations can be achieved.

As also shown in FIG. 1, and illustrated in FIG. 4, the redistributionlayer 20 can be etched with patterns of conductors 22 that electricallyisolate the defective components 12D. A wafer level burn-in test canthen be performed on the substrate 10 to burn-in the components 12.During burn-in test, the substrate 10 is placed in a burn-in oven andsubjected to temperature cycling (e.g., −55° C. to 150° C.) for a timeperiod of from several minutes to several hours or more. At the sametime, the integrated circuits on the components 12 are placed under anelectrical bias. The burn-in test is intended to electrically andphysically stress the integrated circuits and detect failures.

High volume burn-in testing may require the use of “shared” signal andpower circuits among many components 12. Sometimes, one or moredefective components 12D may be defective in a way that could disruptthe normal use of shared resources. For example, a defective component12D may develop a direct internal short between power and ground. Thisshort can drop the voltage on a shared power bus to a level insufficientto power the remaining components 12, which will then also fail theburn-in test.

However, using the method of the invention, during the wafer levelburn-in test the defective components 12D remain electrically isolatedby the configuration of the conductors 22 on the substrate 10, or on thedefective components 12D. Shared resources can thus be employed withoutthe possibility of compromising testing, due to the defective components12D. For example, as shown in FIG. 4, burn-in test circuitry 29 can beelectrically connected in series to all of the components 12 containedin a row, except for the defective component 12D in the row.

As also shown in FIG. 1, and illustrated in FIG. 5, the redistributionlayer 20 can be etched with patterns of conductors 22 that provideselected component clusters C2, C3, C4, or C11. As used herein the term“cluster” means a plurality of discrete components electricallyconnected to form a different component or an assembly.

In particular, the patterns of conductors 22 can be configured toelectrically connect the components 12 in clusters C2, C3, C4, or C11that avoid the defective components 12D. In addition, the data 36 fromthe testing step can be used to determine the “best case” scenario forconnecting the components 12 in clusters to give the highest yield for agiven cluster requirement. Also, in determining the configuration of theclusters C2, C3, C4, or C11, the capabilities of the wafer dicing method(e.g., saw cutting) must be factored in to achieve the desiredconfiguration of clusters.

Following a subsequent singulation process, the clusters C2, C3, C4, orC11 can be used to form packages, modules, and other electronicassemblies, that incorporate the multiple components 12. At the sametime, defective components 12D can be eliminated from the singulatedclusters C2, C3, C4, or C11 such that a yield of the clustered substrate10 (e.g., wafer yield) is improved.

Referring to FIG. 6, in an alternate embodiment, the data 36 from thetesting step can be used to etch the redistribution layer 20 (FIG. 2C),and to also fabricate a test board 48 for burning-in, or otherwisetesting, the substrate 10. Specifically, the test board 48 can befabricated with test sites 50 configured to electrically engage the goodcomponents 12 on the substrate 10 but not the defective components 12D.As such, the test sites 50 can include contacts 51 that are configuredto electrically contact the component contacts 28 on the good components12. However, the test board 48 can also include test sites 50Dconfigured to electrically isolate the defective components 12D on thesubstrate 10. The test board 48 can be patterned with the test sites 50,50D by laser imaging a mask substantially as previously described.Essentially the same data 36 (FIG. 3) can be used for fabricating thetest board 48, as was used to pattern the redistribution layer 20.

Referring to FIGS. 7-7B, a semiconductor package 52 constructed inaccordance with the method of the invention is illustrated. As shown inFIGS. 7 and 7A, the package 52 includes a plurality of terminal contacts64, which comprise solder balls in a grid array. As shown in FIG. 7B,the package 52 also includes a semiconductor die 54 containingintegrated circuits 56 in a desired configuration. The die 54 includesbond pads 58 in electrical communication with the integrated circuits 56contained on the die 54. As shown in FIG. 7A, the bond pads 58 areformed along the center and lateral edges of the die 54. The die 54 alsoincludes a passivation layer 62 formed on a face 60 of the die 54. Thepassivation layer 62 comprises an electrically insulating layer such asBPSG, polyimide or similar material.

As shown in FIG. 7B, the package 52 also includes a plurality ofconductors 22P configured to electrically connect the bond pads 58 onthe die 54 and the terminal contacts 64 on the package 52. Theconductors 22P can be formed by a laser imaging process substantially aspreviously described. The terminal contacts 64 can comprise solder bumpsor balls bonded to the conductors 22P or to bond pads thereon using asuitable bonding process such as soldering, welding or brazing.

As also shown in FIG. 7B, an outer protective layer 66, which comprisesan electrically insulating material, such as polyimide or a patternedresist, is formed on an outside surface of the package to protect theconductors 22P. The outer protective layer 66 can include openings 68for the terminal contacts formed using a laser imaging process.

For fabricating the package 52 the following process sequence can beutilized.

1. Provide a substrate 10 (FIG. 3A) containing a plurality of dice 54having integrated circuits 56, bond pads 58 and passivation layers 62.

2. Test the dice 54 using the test circuitry 14 (FIG. 2B) to evaluateand map the dice 54 on the substrate 10. As previously described,testing can include functionality testing and parametric testing. Forexample, some of the dice may have the speed and functionalcharacteristics required for chip scale packages. Accordingly, thesedice can be further processed. However, some of the dice 54 may not besuitable for chip scale packages, but may be suitable for conventionalplastic packages such as TSOP, TQFP or DIP packages. These dice may beleft alone during the fabrication process and singulated for subsequentprocessing.

3. Form a redistribution layer 20 on the substrate 10 and the dice 54using a deposition process substantially as previously described. Theredistribution layer 20 can comprise a highly conductive metal such ascopper, aluminum, titanium, tungsten, tantalum, molybdenum or alloysthereof.

4. Form a radiant sensitive film 24 (FIG. 2D) on the redistributionlayer 20. The radiant sensitive film 24 can comprise a wet film or a dryfilm, deposited to a desired thickness as previously described, usingtechniques that are known in the art.

5. Expose the radiant sensitive film 24 using a laser scanner 26 (FIG.3), and a laser imaging process substantially as previously described.During the laser imaging process, data from the test step can be used torepair or re-configure defective dice 54, to isolate defective dice 54for burn-in, or to fabricate a matching test board 48 (FIG. 6). Inaddition, a package substantially similar to package 52, can befabricated using clusters of multiple dice. Because the laser scanner 26(FIG. 3) writes the pattern directly onto the radiant sensitive film 24a photomask is not required. In addition, the data from the test stepcan be used “on the fly” to facilitate volume manufacture.

6. Develop the radiant sensitive film 24 to form an etch mask foretching the redistribution layer 20. Depending on the material used toform the radiant sensitive film 24 a suitable commercial developer canbe used to develop the radiant sensitive film 24.

7. Etch the redistribution layer 20 to form the conductors 22P (FIG.7B). The etch step can be performed using a wet etchant that selectivelyetches the redistribution layer 20. As an example, a wet etchant such asH₃PO₄ can be used to etch an aluminum redistribution layer 20.

Alternately, rather than the subtractive process of steps 3-7, anadditive process can be used to form the conductors 22P. Such anadditive process can be performed by depositing a conductive filmthrough openings in a laser imaged radiant sensitive film 24AD (FIG.2H), substantially as previously described.

8. Form the outer protective layer 66 and the pattern of openings 68 inthe outer protective layer 66 for the terminal contacts 64. The outerprotective layer 66 can be initially blanket deposited using a suitabledeposition process, such as spin on, CVD, PCVD or evaporation. Onemethod for forming the openings 68 is to deposit a layer of resist onthe blanket deposited layer. The layer of resist can then be exposedusing a direct imaging process, substantially as previously described,to form a mask for etching the openings 68. As another alternative, theouter protective layer 66 can comprise a photoimageable polymer, such asa layer of resist that is exposed using a direct imaging process andthen developed to form the openings 68.

9. Attach the terminal contacts 64 to the conductors 22P using asuitable process such as soldering, brazing or ball bumping.

10. Burn-in test the dice 54 on the substrate 10. The burn-in test canbe performed by electrically isolating selected dice 54, such asdefective dice, as previously described.

11. Singulate (e.g., saw cut) the substrate 10 into individual packages52.

Referring to FIGS. 8A-8D, a semiconductor package 104 fabricated inaccordance with an alternate embodiment of the invention is illustrated.As shown in FIG. 8A, the semiconductor package 104 includes a packagebody 106 that contains a semiconductor die (not shown). The package body104 can comprise any material used in semiconductor packaging such asplastic, ceramic, or an organic material, such as a glass filled resin.In addition, the package body 106 includes a plurality of land pads 112in electrical communication with the integrated circuits contained onthe die.

Initially, as shown in FIG. 8A, a radiant sensitive film 24B isdeposited on the package body 106 and on the land pads 112. The radiantsensitive film 24B can comprise a commercial resist as previouslydescribed, or another photoimageable polymer such as a thick filmresist. One suitable thick film resist is a negative tone resist sold byShell Chemical under the trademark “EPON RESIN SU-8”. The resist can bedeposited in layers to a thickness of from about 3-50 mils. The resistalso includes an organic solvent (e.g., gamma-butyloracton), and aphotoinitiator. A conventional resist coating apparatus, such as a spincoater, or a meniscus coater, can be used to deposit the resist inviscous form onto the package body 106. The deposited resist can then bepartially hardened (soft-baked) by heating to about 95° C. for about 15minutes or longer.

Next, as shown in FIG. 8B, the radiant sensitive film 24B can be exposedusing a laser scanner 26 (FIG. 3) substantially as previously described,for radiant sensitive film 24 (FIG. 2D). In this case, digital data 36(FIG. 3) for the laser scanner 26 is dependent on the geometry andlocations of the land pads 112.

Next, as shown in FIG. 8C, the radiant sensitive film 24 is developed,and cured if required, to form a mask 108. The mask 108 includesopenings 114 aligned with the land pads 112.

Next, as shown in FIG. 8D, terminal contacts 110 are placed in theopenings 114 and bonded to the land pads 112. For example the terminalcontacts 110 can comprise balls formed of solder or other suitablemetal. Any conventional bonding process such as solder reflow, laserreflow, welding, brazing, or conductive adhesive bonding, can be used tobond the terminal contacts 110 to the land pads 112. The mask 108 has athickness that is less than a height of the terminal contacts 110 suchthat electrical connections can be made to the terminal contacts 110 byelectrodes on a mating component, such as a circuit board or modulesubstrate. In addition, the mask 108 can serve the function of a soldermask, or alternately a rigidifying mask, that helps to anchor theterminal contacts 110 to the land pads 112.

Depending on the application, a thickness of the mask 108 (and theradiant sensitive film 24B) can be selected as required. For solder maskapplications, the mask 108 (and the radiant sensitive film 24B) can bemade very thin (e.g., several microns or less). For rigidifyingapplications, the mask 108 (and the radiant sensitive film 24B) can havea thickness approaching the height of the terminal contacts 110 (e.g.,from ¼ to ¾ a height of the terminal contacts 110).

Thus the invention provides an improved method for fabricating andtesting semiconductor components, improved semiconductor componentsfabricated using the method and a system for performing the method.While the invention has been described with reference to certainpreferred embodiments, as will be apparent to those skilled in the art,certain changes and modifications can be made without departing from thescope of the invention as defined by the following claims.

What is claimed is:
 1. A method for fabricating semiconductor components comprising: providing a substrate containing the components; testing the components on the substrate to evaluate various electrical characteristics and to map the components; and forming a plurality of electrical conductors on the substrate using a laser imaging process and data from the testing step, such that the conductors are configured to repair, re-configure or electrically isolate at least one defective component.
 2. The method of claim 1 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or semiconductor packages.
 3. The method of claim 1 wherein the forming step comprises forming a metal layer on the components, forming a radiant sensitive film on the metal layer, laser imaging the radiant sensitive film to form a mask, and then etching the metal layer through the mask.
 4. The method of claim 1 wherein the forming step comprises forming a radiant sensitive film on the substrate, laser imaging the radiant sensitive film to form a mask having a plurality of openings, and then depositing an electrically conductive material through the openings to form the conductors.
 5. The method of claim 1 wherein the testing step evaluates a gross functionality of the components.
 6. A method for fabricating semiconductor components comprising: providing a substrate containing the components; testing the components on the substrate to identify a defective component; providing a laser scanner; forming an electrically conductive layer on the components; forming a radiant sensitive film on the layer; exposing the film using laser imaging and data from the testing step to form a mask; etching the layer through the mask to form a plurality of conductors configured to repair or to electrically isolate the defective component; and burn-in testing the components.
 7. The method of claim 6 wherein the components comprises memory devices and the conductors re-configure the defective component in a selected format.
 8. The method of claim 6 wherein the conductors substitute redundant circuitry to repair the defective component.
 9. The method of claim 6 wherein the components comprises a plurality of component contacts and the conductors interconnect or electricity isolate selected component contacts on the defective component.
 10. The method of claim 6 wherein the testing step evaluates a gross functionality of the component.
 11. The method of claim 6 wherein the testing step evaluates various electrical characteristics of the components.
 12. The method of claim 6 wherein the testing step maps the components on the substrate.
 13. The method of claim 6 wherein the components comprise a plurality of component contacts and the testing step evaluates pad leakage from the component contacts.
 14. The method of claim 6 wherein the testing step comprises providing a test circuitry configured to apply test signals, and then electrically connecting the test circuitry to the components using a probe card.
 15. The method of claim 6 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 16. A method for fabricating semiconductor components on a substrate comprising: testing the components on the substrate to identify and locate at least one defective component and at least one good component; and forming a plurality of electrical conductors on the substrate using a laser imaging process and data from the testing step, the conductors configured to electrically connect the good component to a test circuitry and to electrically isolate the defective component from the test circuitry, the test circuitry comprising a burn-in test circuitry.
 17. The method of claim 16 wherein the test circuitry comprises functionality test circuitry.
 18. The method of claim 16 wherein the forming step comprises forming a metal layer on the components, forming a radiant sensitive film on the metal layer, laser imaging the radiant sensitive film to form a mask, and then etching the metal layer through the mask.
 19. The method of claim 16 wherein the forming step comprises forming a radiant sensitive film on the substrate, laser imaging the radiant sensitive film to form a mask having a plurality of openings, and then depositing an electrically conductive material through the openings to form the conductors.
 20. A method for fabricating semiconductor components on a substrate comprising: testing the components to identify good components and defective components; providing a laser scanner; forming a plurality of electrical conductors on the substrate using the laser scanner and data from the testing step, the conductors configured to provide electrical paths to the good components and to electrically isolate the defective components; and burn-in testing the good components by applying test signals through the conductors while the defective components remain isolated.
 21. The method of claim 20 wherein the forming step comprises depositing a metal layer on the components, depositing a radiant sensitive film on the layer, exposing the film using the laser scanner and the data to form a mask, and then etching the layer through the mask to form the conductors.
 22. The method of claim 20 wherein the forming step comprises forming a radiant sensitive film on the substrate, laser imaging the radiant sensitive film to form a mask having a plurality of openings, and then depositing an electrically conductive material through the openings to form the conductors.
 23. A method for fabricating semiconductor components comprising: providing the components on a substrate; testing the components to evaluate and map the components; forming an electrically conductive layer on the components; forming a radiant sensitive film on the layer; providing a laser scanner configured to laser image the film; exposing the film using the laser scanner and data from the testing step to form a mask; etching the layer through the mask to form a plurality of conductors configured to provide electrical paths to the components on the substrate while electrically isolating at least one component on the substrate; and burn-in testing the components while the at least one component remains electrically isolated.
 24. The method of claim 23 wherein the testing step evaluates a gross functionality of the components.
 25. The method of claim 23 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 26. The method of claim 23 wherein the testing step evaluates at least one electrical characteristic of the components.
 27. A method for fabricating semiconductor components comprising: providing the components on a substrate; testing the components by performing functionality and parametric tests to locate good components and defective components; forming a radiant sensitive film on the substrate; providing a laser scanner configured to laser image the film; exposing the film using the laser scanner and data from the testing step to form a mask comprising a plurality of openings; and depositing an electrically conductive material in the openings to form a plurality of conductors configured to provide electrical paths to the good components while electrically isolating the defective components.
 28. The method of claim 27 further comprising following the depositing step burn-in testing the good components.
 29. The method of claim 27 wherein the testing step comprises providing a test circuitry configured to apply test signals, and then electrically connecting the test circuitry to the components using a probe card.
 30. A method for fabricating semiconductor components on a substrate comprising: testing the components on the substrate to identify good components and at least one defective component; forming a plurality of electrical conductors on the substrate using a laser imaging process and data from the testing step, the conductors configured to electrically connect the good components in one or more clusters that exclude the defective component; and burn-in testing the good components.
 31. The method of claim 30 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 32. The method of claim 30 wherein the forming step comprises forming a metal layer on the components, forming a radiant sensitive film on the metal layer, direct imaging the radiant sensitive film using to form a mask, and then etching the metal layer through the mask.
 33. The method of claim 30 wherein the forming step comprises forming a radiant sensitive film on the substrate, laser imaging the radiant sensitive film to form a mask having a plurality of openings, and then depositing an electrically conductive material through the openings to form the conductors.
 34. A method for fabricating semiconductor components on a substrate comprising: testing the components on the substrate to identify a defective component; forming an electrically conductive layer on the components; forming a radiant sensitive film on the layer; providing a laser scanner configured to laser image the film; exposing the film using the laser scanner and data from the testing step; developing the film to form a mask; etching the layer through the mask to form a plurality of conductors on the substrate, with at least some of the conductors configured to electrically connect selected components in one or more clusters that exclude the defective component; and burn-in testing the selected components while the defective component remains excluded.
 35. The method of claim 34 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 36. The method of claim 34 wherein the testing step evaluates electrical characteristics of the components.
 37. A method for fabricating semiconductor components on a substrate comprising: testing the components on the substrate by performing functionality or parametric tests to identify at least one defective component; forming a radiant sensitive film on the substrate; providing a laser scanner configured to laser image the film; exposing the film using the laser scanner and data from the testing step; developing the film to form a mask comprising a plurality of openings; and depositing an electrically conductive material in the openings to form a plurality of conductors on the substrate, with at least some of the conductors configured to electrically connect selected components in one or more clusters that exclude the at least one defective component.
 38. The method of claim 37 wherein the testing step evaluates electrical characteristics of the components.
 39. The method of claim 37 wherein the testing step comprises providing a test circuitry configured to apply test signals and electrically connecting the test circuitry to the components using a probe card.
 40. A method for fabricating semiconductor components on a substrate comprising: testing the components on the substrate to identify at least one good component and at least one defective component; forming a test board using a laser imaging process and data from the testing step, the test board comprising a plurality of test sites configured to electrically engage the good component but not the defective component; and burn-in testing the good component using the test board.
 41. The method of claim 40 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 42. The method of claim 40 further comprising forming a plurality of conductors on the components using a laser scanner and the data.
 43. A method for fabricating semiconductor components on a substrate comprising: testing the components to identify good components and at least one defective component; providing a test board; forming an electrically conductive layer on the test board; forming a radiant sensitive film on the layer; providing a laser scanner configured to laser image the film; exposing the film using the laser scanner and data from the testing step to form a mask; and etching the layer through the mask to form a plurality of test sites on the test board configured to provide electrical paths to the good components while electrically isolating the defective component.
 44. The method of claim 43 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 45. The method of claim 43 wherein the test board is configured to perform a burn-in test on the components.
 46. A method for fabricating semiconductor components on a substrate comprising: testing the components to identify good components and at least one defective component; providing a test board; forming a radiant'sensitive film on the substrate; providing a laser scanner configured to laser image the film; exposing the film using the laser scanner and data from the testing step to form a mask comprising a plurality of openings; and. depositing an electrically conductive material in the openings to form a plurality of test sites on the test board configured to provide electrical paths to the good components while electrically isolating the defective component.
 47. The method of claim 46 wherein the substrate comprises a semiconductor wafer and the components comprise semiconductor dice or packages.
 48. The method of claim 46 wherein the test board is configured to perform a burn-in test on the components.
 49. A method for fabricating a semiconductor component comprising: providing a plurality of component contacts on a surface of the component; forming a radiant sensitive film on the surface and on the component contacts; exposing the film using a laser imaging process to form a plurality of openings aligned with the component contacts; and forming terminal contacts in the openings and on the component contacts.
 50. The method of claim 49 wherein the laser imaging process is performed using a laser scanner.
 51. The method of claim 49 wherein the terminal contacts comprise solder balls. 